Which Reg to start the Dive Using?

[Sidemount_Stu]

OK, this may be a stupid question.... but is there a particular regulator (Short hose, left, or long hose, right) that should always be the the regulator i start breathing from on a dive?

(I understand this is perhaps specific to the hose config i use, which as described, is long hose right, short hose left... and it's the ONLY configuration i'm interested in responses for.)

I have my own theories, but they conflict with each other... as far as i can see, starting with the short hose, left cylinder reg in use, works better for me personally, but is perhaps not so considerate to the possibility of a gas issue/failure on entry. Or starting with long hose, right cylinder in use, is considerate to my buddy at entry, and toward end of dive, but is less convenient for myself.

I'd be interested to hear which regs (left or right cylinder) people generally start with, and importantly... WHY?

Is there a standard?
Is it set in stone?
Is it just personal preference?
What do you guys consider when making this choice for yourselves?

Thanks....

 

[Patoux01]

Many will be happy saying you "Sidemount has no standards", imho that's ****.

My view is that if something goes wrong, it will generally be at the beginning of the dive, so I start with the long hose ready to be donated. In the same way, I ascend with the long hose ready to be donated. I believe Steve Martin recommends beginning with the long hose, though I'd have to go through a few hours of video to confirm that, so I won't do it.

How would it be less convenient for you to use the LH?

 

[Dive Right In Scuba 2]

I personally begin the dive with the long hose for the fact that I always perform an S drill with my buddy which requires me to donate it and switch to short hose. That allows me to verify proper function of both regs/tanks under the water. YMMV

 

[tbone1004]

depends, but here's my thoughts

1/6 long hose, 1/3psi short hose, 1/6 long hose then turn *puts you on long hose for the first part of the dive which is most likely to find failure, and last part of the dive which is worst case scenario*, stay on long hose for 1/6psi, then ride the short hose the rest of the way out holding more air on the long hose for your buddy.

For OW, I do the same thing, just do first 1/6, then 1/3's until it's time to go up.

 

[Patoux01]

And I might as well add, when I find a "difficult" place during a dive (ie some "restrictions" that I've been through), I will always switch to the LH. For someone that is very experienced maybe it doesn't matter, but I still, at this point, consider it safer to give something that is 100% sure to be working and not 99.99%. And it's easier to give it (yes I know, drill drill drill should fix this, but it somehow doesn't)

 

[Sidemount_Stu]

Thanks guys.... that has pretty much confirmed what i was thinking, i just needed to see that my rationalisation was based on the correct thought process.

Exactly as has been described, my primary thought about using long hose first, was based around the most likely times for Failure/incident is at the start of the dive, so having the long hose readily donatable makes a lot of sense. Likewise at the end of the dive when if someone has messed up their gas planning, it's (obviously) toward the end of the dive that they'll be most likely to run short an again, having the LH easily donatable at this point makes a lot of sense.

This is exactly why i figured the answer i would get (and agree with) is start with LH!

The "only" reason i referred to it as being less convenient, was purely that if ending the dive on the short hose, instead of LH, means the LH can be stowed during safety stop, or 6m deco stop etc, ready for a quick exit upon surfacing etc.... i'm aware this is not a big issue.... just something that crossed my mind and made me question how others may or may not do it.

and since it was raised.... my default gas management is as follows:

LH - 1/6
SH - 1/3
LH - 1/6 - Turn
LH - 1/6
SH - 1/3
LH - 1/6 - End of Dive

Keeping 1/3 in each cylinder as reserve.

I presume this is pretty standard..... ?

 

[tbone1004]

just switch to short hose on ascent or stow the long hose while breathing off of it, just unloop it and have it come straight up and tuck it back in.

 

[Subcooled]

is there a particular regulator (Short hose, left, or long hose, right) that should always be the the regulator i start breathing from on a dive?

I keep both cylinders within 20bar/300psi from each other (230 bar / 3300 psi cylinders). This translates to:

1/12 initially, and then 1/6, 1/6, 1/6...
with an additional switch when the first cylinder reaches the turn around pressure.

This is not a lot of work as every regulator switch only takes a few seconds (maybe three). A more frequent regulator switch keeps the pressures closer together, which is good.

 

[tbone1004]

300psi might be a bit excessive, but it depends on how anal you want to be, I don't bother checking my SPG's often enough to deal with switching every 300psi, especially on smaller tanks. On the big boys you may want to do it every 12th, which is about 300psi on the steel tanks, but that is far too many regulator switches for me to want to deal with.... I can deal with a slight difference in ballast on each side. Biggest steel tanks have 12lbs of air in them, so by doing a switch every sixth you are only ever 2lbs off on any given tank, maximum of 25CF, not a huge deal when each of those bottles has about 150cf.

 

[Sidemount_Stu]

I only use 12l steel cylinders, so basically aim to keep the cylinders within about 30-35 Bar of each other... Seems to work ok, but not tried Ali cylinders yet though.